1. Field of the Invention
This invention relates to diagnosing internal combustion engines electronically.
2. Description of the Prior Art
It is known in the prior art that the turbocharger commonly used with internal combustion engines, particularly diesel engines, is an important factor of engine health. First, it is necessary that the turbocharger deliver air under pressure to the air intake manifold of the engine in desired quantities and pressures. And, due to its location at the inlet to the engine, any tendency of the turbocharger to disintegrate into small pieces can totally wreck an engine due to ingestion of the pieces into the cylinders of the engine. Many factors, such as drag due to bent blades, warped heat shields and end play, and incipient bearing failure, will show up in turbocharger testing. In the prior art, it has been common to test a turbocharger by mapping pressure ratio across the turbocharger at various engine speeds and at various turbocharger speeds, while the engine is fully loaded, thereby delivering a maximum amount of hot exhaust gas to drive the turbine thereof, the engine being mounted in a vehicle situated on a dynomometer which provides the load to the engine. However, a dynomometer is a very expensive and cumbersome machine; further, dynomometers are frequently not available at locations where engines require testing. In such cases, no practical tests are available in the prior art.